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United States Patent |
5,199,727
|
Lai
|
April 6, 1993
|
Steerable wheel assembly for a roller skate
Abstract
A steerable wheel assembly for use on a roller skate is disclosed. The
wheel assembly consists of a wheel having a roller bearing inserted into
each side thereof and a shaft installed between the roller bearings. The
shaft has journals machined on each end thereof which are fitted into
inner rings of the aforementioned roller bearings to enable the wheel to
rotate. Machined through the center of the shaft is a channel having a
flat upper surface, a lower surface and two slanted surfaces, into which
an axle is inserted. The axle includes four flat surfaces and, more
specifically, two slanted surfaces which are parallel to and offset a
predetermined clearance distance from the two slanted surfaces of the
channel, a top surface and a bottom surface. The top and bottom surfaces
of axle the are parallel to and positioned at a predetermined distance
from the upper and lower surfaces of the channel respectively. The axle
pivots on centered ball bearings and is supported on the bottom by elastic
cushions. When a skater learns to alter the center of gravity or exerts
more leg pressure on one of the roller skates equipped with the invention
herein, the aforementioned axle sways to the biased side by pivoting on
the aforementioned ball bearings, thereby causing the wheel to cant
towards the same side and results in the body turning in the desired
direction.
Inventors:
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Lai; Kuo J. (No. 30, Alley 9, Lane 25, Chin-Li St., Tou-Cheng Shiang, Taipei Shian, TW)
|
Appl. No.:
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845154 |
Filed:
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March 3, 1992 |
Current U.S. Class: |
280/11.28; 280/11.19; 280/11.223; 301/5.301; 301/5.306; 301/105.1 |
Intern'l Class: |
A63C 001/24 |
Field of Search: |
280/11.28,11.19,11.22,11.23,11.25,11.27,87.042
301/5.3,5 R,109,105 R
|
References Cited
U.S. Patent Documents
311936 | Feb., 1885 | Wisewell | 280/11.
|
329927 | Nov., 1885 | Mendenhall | 280/11.
|
3331612 | Jul., 1967 | Tietge | 280/11.
|
4123076 | Oct., 1978 | Passoni | 280/11.
|
4603868 | Aug., 1986 | Schutz | 280/11.
|
Primary Examiner: Culbreth; Eric D.
Attorney, Agent or Firm: Bacon & Thomas
Claims
What is claimed is:
1. A steerable wheel assembly for use on a roller skate comprising:
a) a hollow wheel, having first and second ends, including a bearing
housing molded therein at both of said ends, with a reduced diameter
compartment molded in between said bearing housings;
b) first and second roller bearings each of which is mounted in a
respective one of said bearing housings;
c) a shaft received in said reduced diameter compartment of said hollow
wheel, said shaft including a journal formed on each end thereof, each of
said journals being inserted into a respective one of said roller bearings
such that said hollow wheel may rotate relative to said shaft upon said
first and second roller bearings, said shaft further including a passage,
formed through the center line of the shaft, having an upper surface, a
lower surface and two slanted surfaces, a first threaded hole tapped
through a central portion of said shaft, substantially perpendicular to
said passage which entirely penetrates the upper and lower surfaces of
said passage and said shaft, and second and third threaded holes which
extend through said shaft into said passage;
d) an axle received within said passage with each end of said axle
protruding from said passage and including a threaded hole formed therein,
said axle having four flat surfaces including top and bottom surfaces that
are parallel to and positioned a predetermined distance from the upper and
lower surfaces of said passage respectively, said axle further including
centrally located, hemispherical recesses formed in the top and bottom
surface of said axle, the remaining two flat surfaces of said axle being
flush with the two slanted surfaces of said passage with a predetermined
clearance therebetween;
e) first and second ball bearings, each of bearings being positioned
between one of said hemispherical recesses of said axle and said first
threaded hole formed in said shaft with a set screw being installed into
each end of said first threaded hole over a respective ball bearing in
order to govern the pivoting movement of the axle;
f) first and second cylindrical cushions, each of said cylindrical cushions
being located in a respective one of said second and third threaded holes
in said shaft between said axle and a respective set screw in order that
the set screw may adjust the elasticity applied to the axle, wherein said
axle may pivot on said first and second ball bearings upon an application
of force to said axle during use of said steerable wheel assembly whereby
the action of said axle causes said hollow wheel to cant so as to permit
said wheel assembly to turn.
2. The steerable wheel assembly of claim 1, wherein said cushions are
constructed out of an elastic material in the shape of a cylinder.
3. The steerable wheel assembly of claim 1, further comprising resilient
contact bushings located between said ball bearings and their associated
set screws.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention pertains to a steerable wheel assembly and, more
specifically, an improved wheel assembly that, when installed on roller
skates or the like, provides excellent control capability while using one
leg, two legs or executing relatively small radius sharp turns.
2. Description of the Prior Art
As indicated in FIG. 1, a conventional roller skate (10) consists of a
number of assembled parts, including a boot (11), a base plate (12), a
shock reducer (13), four wheels (14), axles (15) and a movement controller
(16).
Such conventional roller skates have a fixed axle design so there is no way
to directly execute a turn and the height of the legs above the ground
must be adjusted to change the skating direction. More specifically,
during the execution of a turn, the outer leg must be lifted and placed in
front of the inner leg and only after the completion of this action can
the body be turned in the desired direction. As a result, the utilization
of a conventional roller skate produces the following disadvantages during
the execution of turns:
First, since the conventional roller skate is turned indirectly, control is
inadequate and it is difficult for beginning skaters to master the
required technique.
Second, since only one foot is on the ground during a turn when using
conventional skates, overall skating stability is reduced and it is
firstly easy to slip and fall because of the imbalanced center of gravity.
Third, conventional roller skates exhibit a relatively large turning radius
during turn execution and therefore require larger rink areas to afford
sufficient skating.
Fourth, it is impossible to turn on one foot only with conventional roller
skates since both feet must be alternated in position to complete the turn
and, therefore, no other skating maneuvers can be performed while
executing a turn.
SUMMARY OF THE INVENTION
The main object of the invention herein is to provide an improved roller
skate wheel assembly that directly influences the turning efficiency of
roller skates, while also enabling a higher degree of skater control.
Another object of the invention herein is to provide a kind of improved
roller skate wheel assembly that enables the execution of a turn while
both legs are in contact with the ground in order to accord increased
stability during turning maneuvers.
A further object of the invention is to provide an improved roller skate
wheel assembly that enables the execution of a varied and continuous
series of turning maneuvers with one leg or two legs such that when one
leg is utilized to execute a turn, the other leg is free to undertake
other performing movements.
These and other objects of the invention are accomplished by providing a
wheel having roller bearings installed at both sides thereof and a shaft
enclosed in a compartment between the roller bearings. At the ends of the
shaft are journals which are inserted into inner rings of the roller
bearings so as to enable the wheel to rotate. Furthermore, a channel is
machined through the shaft. The channel has an upper surface, a lower
surface and two slated surfaces through which an axle is inserted. The
axle has two slanted surfaces that are parallel to the slanted surfaces of
the channel and are sized to maintain a predetermined clearance between
the slanted surfaces of the channel and the axle. The axle also has a top
surface and a bottom surface which are set a given distance away from the
upper and lower surfaces of the channel respectively. In addition, the
axle is suspended at the center on ball bearing pivot points and is
simultaneously supported on the bottom surface by components made out of
an elastic material. When a skater leans his body to alter the center of
gravity or exerts more leg force downward over one roller skate, the axle
will say to one side, pivoting on the ball bearings, causing the wheel to
cant in the direction of the altered center of gravity or leg bias to
thereby enable the body of the skater to turn.
To thoroughly understand the remaining objectives and advantages of the
invention, the appended drawings and accompanying description of a
preferred embodiment of the invention are provided below for further
reference.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 depicts a conventional roller skate.
FIG. 2 is a side view of a roller skate equipped with wheel assemblies
according to the present invention.
FIG. 3 is an exploded view of one of the roller skate wheels of the
invention.
FIG. 4 is a cross-sectional view of the roller skate wheel shown in FIG. 3
in an assembled state.
FIG. 5 if a cross-sectional side view which depicts the steering mechanism
of the roller skate wheel assembly of the invention.
FIG. 6 is a cross-sectional view of the roller skate wheel assembly of the
invention, similar to that shown in FIG. 4, but depicting the axle at a
skewed angle.
FIG. 7 is a cross-sectional view of the roller skate wheel assembly of the
invention showing details of the axle,
FIG. 8 is the rear view of the invention showing the position of roller
skate wheel during a right turn, illustrating that when a right turn is
executed, the right side of the roller skate wheel is inclined to the
right, while the left side of the roller skate is canted upward to the
left.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The steerable wheel assembly of the present invention will now be explained
in detail with reference to FIGS. 2-8. FIG. 2 shows front and rear roller
skate wheels 20A and 20B according to the invention installed on a roller
skate boot 30. As indicated in FIG. 2, each roller skate boot 30 requires
a forward roller skate wheel 20A and rear roller skate wheel 20B,
resulting in a roller skate boot with fore and aft roller skate wheels,
which is different than the conventional roller skate boot shown in FIG. 1
that has four roller skate wheels. Of course, the roller skate wheels 20A
and 20B of the present invention can also be installed on a roller skate
boot originally equipped with four roller skate wheels and, furthermore, a
roller skate boot equipped with the roller skate wheels 20A and 20 of the
present invention can be used to skate on both ice and other smooth
surfaces.
As indicated in FIG. 3, the roller skate wheel assemblies of the present
invention each include a hollow wheel 2, a section which is preferably
made out of pliable resinous material and formed with two bearing housings
21 molded inside. Bearing housings 21 located respective roller bearings 3
within wheel 2 in order to permit rotation of wheel 2. A compartment 22 is
molded between the two aforementioned bearing housings 21 to accommodate
the insertion of a shaft 4. As indicated in FIGS. 3 and 4, shaft 4 is
adapted to be inserted into the compartment 22 in the wheel 2. Both ends
of shaft 4 are reduced in relative outer diameter to form journals 41
which fit into the inner rings 31 of the aforementioned roller bearings 3.
By this construction, shaft 4, roller bearing 3 and wheel 2 may be
assembled into a single composite unit.
Machined through the center of shaft 4 is a passage 42. Passage 42 has an
upper surface 43 and a lower surface 44 and two slanted surfaces 45.
Passage 42 serves as a quadrilateral passage for the insertion of an axle
5, while also guiding the movement of axle 5 and the directional
orientation of wheel 2 as will be explained more fully below. As indicated
in FIG. 7, passage 42 determines the direction of wheel 2 based on the
upper limit (a) and lower limit (b) along an identical perpendicular line
imposed by inner slanted surfaces 45.
Referring once again to FIGS. 3 and 4, the axle 5 is adapted to be inserted
through passage 42 so that the end sections of the axle 5 protrude from
the two ends of shaft 4. Moreover, there is countersunk threaded hole 51
on each end of axle 5 to accommodate the fastening of a screw 50 to each
of the ends which (as indicated in FIG. 2) secure the roller skate wheels
20A and 20B to the roller skate frame 12. There are four flat surfaces
machined onto axle 5, i.e, a top surface 53, a bottom surface 54 and two
angularly offset surfaces 55 situated at approximately 45 degrees and 225
degrees, respectively, relative to the center line of axle 5. When the
axle 5 is installed inside passage 42, the top surface 53 and the bottom
surface 54 of axle 5 are positioned parallel to the upper surface 43 and
the lower surface 44 of passage 42 respectively, with a predetermined
distance 40 maintained between the top surface 53 of the axle 5 and the
upper surface 43 of passage 42 as well as between the bottom surface 54 of
axle 5 and the lower surface 44 of passage 42. The angularly offset
surfaces 55 of axle 5 make light contact with the slanted surfaces 45 of
passage 42 such that a tiny clearance (the size of the clearance is not
indicated in FIG. 7) is maintained between the angularly offset surfaces
55 of axle 5 and the slanted surfaces 45 and passage 42 to enable movement
of axle 5 within passage 42. The aforementioned slanted surfaces 45, the
axle 5, the upward and downward movement range allowed by the fixed
distance 40 within passage 42 and the roller wheel 20A or 20B all
contribute to produce a variable range of turning angles as will be
discussed below.
As indicated in FIGS. 3 and 4, in order to support the pivoting movement of
axle 5, a bearing recess 56 is machined at the center of both the top
surface 53 and the bottom surface 54 of axle 5. Bearing recess 56 holds a
ball bearing 57 in place on each of the aforesaid surfaces. More
specifically, one portion of each ball bearing 57 is received within the
bearing recess 56, while the other portion of each ball bearing 57 is
received within the lower ends of threaded holes 46 tapped into the top
surface 47 and into the bottom surface of shaft 4. An Allen-head set screw
59 is then installed through each of the aforementioned threaded holes 46
to exert a suitable degree of pressure that will allow ball bearings 57 to
revolve freely when implaced as a pivot point so as to enable axle 5 to
turn. The threaded holes 46 tapped into the top surface 47 and the bottom
surface 48 of shaft 4 penetrate through to the upper surface 43 and the
lower surface 44 of passage 42 respectively. A resilient contact bushing
58 is positioned between each ball bearing 57 and a lower tip of the
Allen-head set screws 59 which serves to prevent the wearing away of the
aforesaid ball bearing 57.
In order to enable axle 5 to return to its original level position, two
threaded holes 49 are tapped into the bottom surface 48 of shaft 4. The
centers of threaded holes 49 are in line with the center threaded hole 46,
also tapped into bottom surface 48 of the shaft 4. Each of the threaded
holes 49 accommodate both the implacement of a cylindrical cushion 6 and
the installation of an Allen-head set screw 61. Set screws 61 adjustably
secure the cylindrical cushions 6 such that the resulting tension causes
axle 5 to revert to the original level position shown in FIG. 4, while
also providing weight support and absorbing shock. Of course, cylindrical
cushion 6 can comprise a compressible spring or other component with
similar elastic properties.
Since the details contained in the appended drawings and the accompanying
explanations refer only to a preferred embodiment of the invention, they
should not be construed as constituting any intended limitation whatsoever
and the substitution of any individual component or components which
duplicate the basic innovations thus far described should be considered as
within the principles and scope of the invention.
The following section shall explain how the aforementioned roller wheels
20A and 20B of the invention herein are controlled on the roller skate
boot to execute a right turn. As indicated in FIG. 6, during execution of
a right turn, the skater transfers his body's center of gravity to the
right by exerting additional leg pressure over the right side of the
skate. This action causes the right end of axle 5 with ball bearing 57
serving as a pivot point to travel downward along the slanted surfaces 45
inside passage 42, while the left end of axle 5 travels upward along the
upper slanted surfaces 45 inside passage 42. The two ball bearings 57
positioned on shaft 4 serve as the pivot points enabling the movement of
the axle 5, as illustrated by the canted state of the axle 5 in FIG. 6. As
a result, the right side of wheel 2 leans downward to the right (note that
left and right movement is produced from the same axle), while the left
side of wheel 2 is canted upward to the left (as best shown in FIG. 8).
Under these conditions, roller skate wheel 20A or 20B is caused to turn
towards the right and enables the body of the skater to switch direction
to the right. Since the principles underlying the execution of a left turn
are identical to those for executing a firth turn, an additional
explanation is not necessary. However, it should be noted that if the
movement of the rear roller wheel 20B is attributed to the same
directional action produced by the axle 5 relative to the direction of the
slanted surfaces 45 inside the passage 42 as that for the front roller
wheel 20A, then the rolling direction of the rear wheel 20B and the front
roller wheel 20A are identical. But, if the movement of the rear roller
wheel 20B attributed to the action of the axle 5 relative to the direction
of the slanted surfaces 45 inside the passage 42 is opposite to that of
the front roller wheel 20A, then the turning capability of the roller
skate will be significantly increased in magnitude and the required
turning radius will be relatively smaller. In addition, the lateral stress
on the roller skate will depend on the combined forces produced by the
turning angle of the roller skate as well as the lean angle of the body.
Thus, when the lean angle and the lateral stress are small, the angle of
the turn will be small and when the lean angle and the lateral stress is
great, then the angle of the turn will be large. When the body of the
skater returns to a balanced state and the leg force is equally
distributed on the roller skates, then axle 5 reverts to a level state
parallel to the ground surface as indicated in FIG. 4. Since axle 5 is
suspended in a balanced manner inside passage 42, the roller wheels 2
track ahead in a straight line. Similarly, when roller wheels 2 leave the
ground surface and the downward force on the roller skate is removed, the
elastic action of the cylindrical cushions 6 serves to return axle 5 back
to a level state.
As described above, due to the capability of harness shafts in the center
of gravity to execute directional changes by changing the lean angle of
the body and altering the downward force exerted by the legs, the improved
roller skate wheel assembly of the present invention herein provides
excellent responsiveness and extreme ease in turning control. Furthermore,
since turns can be executed with both roller skates on the ground, the
invention herein offers exceptional stability. Moreover, turns can also be
executed with both roller skates or just one roller skate on the ground, a
capability that enables a skater to perform a wider variety of skillful
maneuvers. Also, since the invention herein has a relatively small turning
radius, it can be utilized in relatively small areas and still retain
exceptional turning performance. Although describe for use in a two wheel
roller skate environment, it should be understood that the roller skate
wheel assembly of the present invention may be used in various embodiments
such as four-wheel roller skates, linear roller skates, skate boards and
push carts, without losing the unique advantages of the invention herein.
In general, the invention is only intended to be limited by the scope of
the following claims.
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